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Patented Mar. 19, 1889..

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N0.399,994. Patented Mar. 19, 1889.

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UNITED Srnrns arnnr rrrcE.

SAMUEL I-I. JOHNSON AND CHRISTOPHER O. HUTCHINSON, OF VEST HAM, COUNTY OF ESSEX, ENGLAND.

METHOD OF FORCING FLUIDS AND SEMI-FLUIDS BY MEANS OF COMPRESSED AIR.

SPECIFICATION forming part of Letters Patent No. 399,994, dated March 19 1889.

Application filed March 8, 1887. Renewed October 22, 1888- Serial No. 288,879. (No model.) Patented in England July 4,

I 1885, No. 8,141.

To aZZ whom it may concern:

Be it known that we, SAMUEL H. JOHNSON, of Vest Ham Hall, Essex, England, and CHRISTOPHER C. Hurcninson, of the parish of Vest Ham, Essex, England, subjects of the Queen of Great Britain, have invented new and useful Improvements in Methods of Forcing Fluids and Semi-Fluids by Means of Compressed Air, (for which we have obtained Letters Patent in Great Britain, No. 8,141, dated July at, 1885,) of which the following is a speci fication.

It has been found inconvenient or impracticable in the case of certain fluids and semifiuids to employ pumps for forcing them under pressure in consequence of the specific character of the fluids. Either they are corrosive and act on the materials from which most pumps are constructed, or else, in the case of semi-fluids containing large proportions of fibrous and other matters, have a tendency to accumulate and obstruct the valves and other working parts of pumps. In such cases it has been heretofore common to employ compressed air for the purpose of forcing such liquids and dispense entirely with pumping them and the consequent difiiculties above indicated. The receptacle is provided with an inlet-pipe, by means of which compressed air is introduced above the level of the material therein. It is also provided with an outlet-pipe from the lower part, by means of which the material is conducted away under the pressure of the eir in the upper part of the receiver. This arrangement is now prin cipally used for forcing corrosive fluids to a superior level-such as sulphuric acid in sulphuric-acid chambers and more frequently pressed air thus blown away into the atmosphere a large proportion of the whole potential energy necessary for forcing the liquid by this system is lost.

Now the object of this invention is to secure the advantages of forcing with compressed air in the cases above mentioned without the disadvantages above indicated, and to this end we proceed as follows: Te provide a series of two or more hermetically-cl0sed receptacles, and where it is desired to maintain a continuous pressure of the material in the forcing-main, such as would be requisite when a series of filter presses are being worked therefrom, we prefer to employ three receptacles. lVe fill one of the receptacles with compressed air to the pressure at which we desire to work. We then fill another of the receptacles with the material to be forced. XV e then open a cock or valve communicating with a pipe which connects the top of the first and second receivers. \Ve then pump water into the first receiver by any convenient pump of ordinary construetion, and by this means we displace the air in the first receiver, forcing it into the second, which. in its turn forces the material from the second receiver into the pressure-main. As soon as the first receiver becomes filled with water a float is raised, which closes a valve on the end of the pipe by means of which the air flowed into the second vessel. The induction-pipe for the water is provided near the pump with a loaded safety-valve, which is adjusted to deliver the excess of water when the receiver is full, being loaded slightly above the working-pressure in the first receiver when the air is being displaced with the water. The water-pump is then stopped, and the cock in the air-pipe, by means of which the compressed air was transferred from the first to the second receptacle, is then closed. At this stage the proportions of the different parts are so arranged that the second receiver, which is of equal size with the first, shall contain all the compressed air forced out of the first receiver at a slightly higher pressure and a small quantity of the material in process of being forced by the pneumatic pressure. The first receptacle is provided with an outlet-cock and aircock at the top, communicating with the atmosphere, and these being opened the water is allowed to run away. So soon as the second receptacle is emptied, a float at the bottom of it closes a valve, which prevents the air escaping into the pressure-main for the material being forced. No. 2 receptacle is then in the condition of No. 1 at the commencement of the operation--namely, filled with the same volume of compressed air and under the same pressure. The third receptacle, which has been previously filled with the material to be forced, is treated in all respects in the same way as the second receptacle had previously been when the material from it was being forced by the compressed air from the first receptacle, the water being pumped into the second receptacle and otherwise manipulated as already described in reference to the first receptacle. The first receptacle is then filled with the material to be forced by allowing it to flow in by gravitation or otherwise, and then it in its turn is ready to have its contents displaced by means of the compressed air from the third receptacle so soon as its contents have been forced out, and so the process is repeated continuously, and by this means we obtain the following advantages:

First. Materials can be forced without pumping them which otherwise would obstruct or destroy the valves and other working parts of a pump using only the amount of energy necessary to work an ordinary pump.

Secondly. By using the same volume of compressed air over and over again without allowing it to expand we avoid the loss of power which occurs in the older method of pneumatic forcing by the heat evolved during the compression of the air.

Thirdly. WVe avoid the waste of energy which occurs when the compressed air is blown away to waste after each forcing operation.

There are other advantages which result from the employment of a pneumatic system for forcing materials into filter-presses, such as is due to the elasticity of the compressed air regulating the supply to filter-presses and adapting itself to the requirements of the work to bedone in a way that would not be practicable with any ordinary pump; but these advantages are not peculiar to this system of pneumatic forcing, but are common to the pneumatic forcing system now commonly employed, as above described.

In order that our said invention may be most fully understood and readily carried into effect, we will proceed to describe the drawings hereunto annexed.

Figure 1 is an elevation of apparatus arranged in accordance with our invention. Fig. 2 is a plan, and Fig. 3 is a transverse vertical section, of the same.

The apparatus as here shown is suitable for Supplying sewage-sludge to filter-presses, by

which it is compressed into cakes, and like apparatus may also be employed in forcing other fluids or semi-fluids either for the supply of filter-presses or for other purposes.

A A A are hermetically-closed vessels. They are similar the one to the other, and they are connected at the top by pipes B, on which air-cocks B B are provided. Each vessel communicates with a main, 0, through which the vessel is charged. The connection is by a passage in which is a valve which can be opened or closed at pleasure. These valves are operated by means of hand-wheels D D. The vessels A A A also communicate by other passages with a discharging-main, which also can at pleasure be closed and opened by valves, the valves for this purpose being operated by means of hand-wheels F. The filter-presses to which sludge is to be supplied are put into communication with the main E, when required, by opening valves provided for the purpose, or the main E may lead the fluid or semi-fluid matter, whatever it may be, to any place whereit may be required. At the lower part, also, of each vessel a pipe, G, is connected, and this leads to other pipes, H and l, which are respectively the de-v livery and the suction of. a water-pumping apparatus, K.

H and I are cocks, by opening and closing which either vessel can at pleasure be connected with the pump-suction or with the delivery-pipe.

Within each vessel there is a ball-valve, L, of metal covered with vulcanized india-rubber. It is sufficiently light to float on the sludge or contents of the vessel, and the purpose which it serves is to automatically close the connection between the vessel and the main E immediately the vessel is empty, and also to close the communication between the vessel and the pipe B when the vessel is completely full.

The apparatus may be used as follows: Suppose the vessel or receptacle A to be full of sewage-sludge, the vessel A to be full of compressed air, and the vessel A to be full of water. The vessel A is put in communication with the main E. All other cocks in connection with this vessel are closed, excepting that the pipe 13 is opened to connect this vessel at the top with the neighboring vessel A All cocks in connection with the vessel A are closed, except that which connects it wit-h the delivery-pipe H of the pump. All the cooks in connection with the vessel A are closed, with the exception of that which connects it with the suction-pipe I of the pump. The pump being now set to work, water is drawn from the vessel A and forced into the vessel A thereby displacing the compressed air which the vessel already contains. This compressed air enters the vessel A, while the sludge is forced from this vessel into the main E. WVhen the vessel A is empty, the valve L within it closes the passage to the main E, while the corresponding valve of the vessel A closes that vessel at the top. The pumping apparatus may continue in motion. Any water which it may draw escapes by the weighted valve M, and passes into the servicetank N, with which also the suction of the pumping apparatus can be connected at pleasure. The vessel A is now empty and there is a partial vacuum within it. The next op eration to fill this vessel with sludge, which is done by opening the valve D. The sludge then flows in until the vessel is filled, or nearly so.

The arrangement shown in the drawings is suitable where the sludge is to be drawn from a source raised a few feet above the main 0; but if it be required that the vacuum in the vessel A should raise the sludge from a lower level, then the pumping apparatus K should also be placed lower do\vnsay some twelve feet below the bottom of the vessels A A A-- so that the descent of the water from them may aid the action of the pump. The vessel A being now full of sludge, while the vessel A contains the compressed air and A contains the water, the cycle of operation recommences. The compressed air is transferred from A to A the vessel A is discharged into the main .1, and the water is drawn out from the vessel A Thus the operation goes on, the volume of compressed air being transferred from vessel to vessel without loss of energy. Any description of pumping apparatus may be employed, and in some cases the water under pressure may be drawn from an elevated cistern or other source and the use of a pump in direct connection with the apparatus dispensed with.

It is obvious that the air may in the first instance be compressed by forcing water into one or more of the vessels, While another serves as a receiver for the air which the water displaces.

Any leakage of compressed air which may some air also to be in them when commencing to discharge the contents.

\Ve reserve the apparatus herein described for another application for a patent.

\Vhat we claim, and desire to secure by Letters Patent, is

Our improvementin forcing fluids and semifluids, consisting of introducing water under pressure into a vessel containing compressed air, thereby causing the compressed air to pass into another vessel containing the fluid or semi-fluid and to eject the same, this operation being repeated with the same compressed air successively transferred, without being allowed to expand, from the vessel so discharged to another one charged with the material to be ejected, and thus used over and over, so as to avoid the waste of the energy expended in compressing the air, substan-.

tially as described.

SAM. H. JOHNSON. O. C. HUTCHINSON.

Witnesses:

ERNEST LIDDELL, T. J. ()SMANS, Both of 17 Gracechm'ch Street, London, E. O. 

